Worth noting that when AnandTech did their initial M1 Max review, they never were able to achieve full 400GB/s memory bandwidth saturation, the max they saw when engaging all CPU/GPU cores was 243GB/s - https://www.anandtech.com/show/17024/apple-m1-max-performanc....
I have not seen the equivalent comparisons with M[2-3] Max.
Interesting! There are anecdotal reports here and there on local llama about real world performance, but yeah I'm just reporting what Apple advertises for those devices on their spec sheet